Vibrio coralliilyticus does not normally cause disease in healthy, lab raised Pocillopora damicornis coral specimens at a temperature of 75°F, but becomes pathogenic at higher temperatures. Temperatures above 80°F increase the acceleration and severity of the infection.

Look all I'm saying is that the fact he had a meltdown caused by a heater malfunction increased the likelihood of some nasty sh!t in the tank water. Hot = bacterial breeding ground = more likely to get an infection.